Healthy volunteers and patients with abductor spasmodic dysphonia may be eligible for this study. Candidates will have a physical examination and medical history. (Patients will be videotaped and voice-recorded during the medical interview for review by specialists who will identify the type and severity of their speech disorder.) All candidates will also undergo a procedure called flexible fiberoptic laryngoscopy to record the movement of the vocal folds during speech, breathing and other tasks such as singing, whistling and prolonging vowels. For this test, the inside of the nose is sprayed with an anesthetic (lidocaine) to numb the nasal cavity and a decongestant (oxymetazoline) to widen the nasal passage. Then, a thin flexible tube called a nasolaryngoscope is passed through the nose to the larynx (voice box). A camera attached to the eyepiece of the nasolaryngoscope records the movements of the vocal folds.